Photosynthesis, Chloroplast | Learn Science at Scitable Figure Detail What Is Photosynthesis? Why Is it Important? Most living things depend on photosynthetic cells to manufacture the complex organic molecules they require as a source of energy. Photosynthetic cells are quite diverse and include cells found in green plants, phytoplankton, and cyanobacteria. During the process of photosynthesis, cells use carbon dioxide and energy from the Sun to make sugar molecules and oxygen. These sugar molecules are the basis for more complex molecules made by the photosynthetic cell, such as glucose. Then, via respiration processes, cells use oxygen and glucose to synthesize energy-rich carrier molecules, such as ATP, and carbon dioxide is produced as a waste product. Therefore, the synthesis of glucose and its breakdown by cells are opposing processes. Figure Detail The building and breaking of carbon-based material — from carbon dioxide to complex organic molecules (photosynthesis) then back to carbon dioxide (respiration) — is part of what is commonly called the global carbon cycle. Indeed, the fossil fuels we use to power our world today are the ancient remains of once-living organisms, and they provide a dramatic example of this cycle at work.

The carbon cycle would not be possible without photosynthesis, because this process accounts for the "building" portion of the cycle (Figure 2). However, photosynthesis doesn't just drive the carbon cycle — it also creates the oxygen necessary for respiring organisms. Interestingly, although green plants contribute much of the oxygen in the air we breathe, phytoplankton and cyanobacteria in the world's oceans are thought to produce between one-third and one-half of atmospheric oxygen on Earth. What Cells and Organelles Are Involved in Photosynthesis? Figure 3: Structure of a chloroplast © 2010 Nature Education All rights reserved. Photosynthetic cells contain special pigments that absorb light energy. Different pigments respond to different wavelengths of visible light. Chlorophyll, the primary pigment used in photosynthesis, reflects green light and absorbs red and blue light most strongly. In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll. Chloroplasts are surrounded by a double membrane and contain a third inner membrane, called the thylakoid membrane, that forms long folds within the organelle.

In electron micrographs, thylakoid membranes look like stacks of coins, although the compartments they form are connected like a maze of chambers. The green pigment chlorophyll is located within the thylakoid membrane, and the space between the thylakoid and the chloroplast membranes is called the stroma (Figure 3, Figure 4). Chlorophyll A is the major pigment used in photosynthesis, but there are several types of chlorophyll and numerous other pigments that respond to light, including red, brown, and blue pigments. These other pigments may help channel light energy to chlorophyll A or protect the cell from photo-damage. For example, the photosynthetic protists called dinoflagellates, which are responsible for the "red tides" that often prompt warnings against eating shellfish, contain a variety of light-sensitive pigments, including both chlorophyll and the red pigments responsible for their dramatic coloration. Figure 4: Diagram of a chloroplast inside a cell, showing thylakoid stacks Shown here is a chloroplast inside a cell, with the outer membrane (OE) and inner membrane (IE) labeled.

Other features of the cell include the nucleus (N), mitochondrion (M), and plasma membrane (PM). At right and below are microscopic images of thylakoid stacks called grana. Note the relationship between the granal and stromal membranes. © 2004 Nature Publishing Group Soll, J. & Schleiff, E. Protein import into chloroplasts. Nature Reviews Molecular Cell Biology 5, 198-208 (2004) doi:10.1038/nrm1333. All rights reserved. Figure Detail What Are the Steps of Photosynthesis? Photosynthesis consists of both light-dependent reactions and light-independent reactions. In plants, the so-called "light" reactions occur within the chloroplast thylakoids, where the aforementioned chlorophyll pigments reside. When light energy reaches the pigment molecules, it energizes the electrons within them, and these electrons are shunted to an electron transport chain in the thylakoid membrane. Every step in the electron transport chain then brings each electron to a lower energy state and harnesses its energy by producing ATP and NADPH.

Meanwhile, each chlorophyll molecule replaces its lost electron with an electron from water; this process essentially splits water molecules to produce oxygen (Figure 5). Figure 5: The light and dark reactions in the chloroplast The chloroplast is involved in both stages of photosynthesis. The light reactions take place in the thylakoid. There, water (H2O) is oxidized, and oxygen (O2) is released. The electrons that freed from the water are transferred to ATP and NADPH. The dark reactions then occur outside the thylakoid. In these reactions, the energy from ATP and NADPH is used to fix carbon dioxide (CO2). The products of this reaction are sugar molecules and various other organic molecules necessary for cell function and metabolism. Note that the dark reaction takes place in the stroma (the aqueous fluid surrounding the stacks of thylakoids) and in the cytoplasm. Photosynthesis - Biology with Skinner at The Bush School - StudyBlue the first stage of photosynthesis, the process by whichplants capture and store energy from sunlight. ATP synthase a general term for an enzyme that can synthesize ATP from ADP and inorganic phosphate and release it using a form of energy.

a series of reactions that take place in the stroma of chloroplasts in photosynthetic organisms. The calvin cycle uses ATP and NADPH from the light dependent reactions to produce high-energy sugears. * The material on this site is created by StudyBlue users. StudyBlue is not affiliated with, sponsored by or endorsed by the academic institution or instructor. Words From Our Students "StudyBlue is great for studying. I love the study guides, flashcards and quizzes. So extremely helpful for all of my classes!" Alice , Arizona State University "I'm a student using StudyBlue, and I can 100% say that it helps me so much. Study materials for almost every subject in school are available in StudyBlue. It is so helpful for my education!" Tim , University of Florida "StudyBlue provides way more features than other studying apps, and thus allows me to learn very quickly!??I actually feel much more comfortable taking my exams after I study with this app. It's amazing!" Jennifer , Rutgers University "I love flashcards but carrying around physical flashcards is cumbersome and simply outdated.

StudyBlue is exactly what I was looking for!" Justin , LSU Structural Biochemistry/Cell Organelles/Plant Cell - Wikibooks, open books for an open world Structural Biochemistry/Cell Organelles/Plant Cell Overview[ edit ] An overview of plant cell. Plants are eukaryotes, multicellular organisms that have membrane-bound organelles. Unlike prokaryotic cells, eukaryotic cells have a membrane-bound nucleus. A plant cell is different from other eukaryotic cells in that it has a rigid cell wall, a central vacuole, plasmodesmata, and plastids. Plant cells take part in photosynthesis to convert sunlight, water, and carbon dioxide into glucose, oxygen, and water. Plants are producers that provide food for themselves (making them autotrophs) and other organisms. These are some of the parts common to plant cells: •Cell Wall- smooth layer that provides DNA and protection from osmotic swelling.

•Cell (Plasma) Membrane- it is composed of a phospholipid lipid bilayer (including polar hydrophilic heads facing outside and hydrophobic tails facing each other inside) that makes it semipermeable and thus capable of selectively allowing certain ions and molecules in/out of the cell. •Cytoplasm- it consists of the jelly-like fluid in and around the organelles. •Cytoskeleton- is made up of microtubules, intermediate filaments, and microfilaments. It provides shape the shape of the cell and helps in transporting materials in and out of the cell. • Golgi Apparatus (body/complex)- it is the site where membrane-bound vesicles are packed with proteins and carbohydrates. These vesicles will usually leave the cell through secretion. •Vacuole- stores metabolites and degrades and recycles macromolecules. • Mitochondria - is responsible for cellular respiration by converting the energy stored in glucose into ATP. • Ribosome - contain RNA and proteins for protein synthesis. One type is embedded in Rough ER and another type puts proteins directly into the cytosol.

•Rough Endoplasmic Reticulum (rough ER )- covered with ribosomes, it stores, separates, and transports materials through the cell. It also produces proteins in cisternae, which then go to the Golgi apparatus or insert into the cell membrane. •Smooth Endoplasmic Reticulum (smooth ER)- it has no ribosomes embedded in its surface. Lipids and proteins are produced and digested here. Smooth ER buds off from rough ER to move newly-synthesized proteins and lipids. The proteins and lipids are transported to the Golgi apparatus (where they are made ready for export) and membranes. •Peroxisome- is involved in metabolizing certain fatty acids and producing and degrading hydrogen peroxide. •Nuclear Membrane (envelope)- the an extension of the endoplasmic reticulum that wraps around the nucleus. Its many gaps allow traffic in/out of the nucleus. • Nucleus - it contains DNA in the form of chromosomes or chromatin and controls protein synthesis. • Nucleolus - it is the site of ribosomal RNA synthesis.

•Centrosome- consisting of a dense center and radiating tubules, it organizes the microtubules into a mitotic spindle during cell division. •Chloroplast- conducts photosynthesis and produces carbohydrates, oxygen, and internally ATP and NADPH from captured light energy. •Starch Granule- temporarily stores produced carbohydrates from photosynthesis. Depending on the organism, it can be inside or outside of the chloroplast (if present). Exclusive to Plant Cells[ edit ] Cell Wall[ edit ] The cell wall is a tough, usually flexible but fairly rigid layer that surrounds the plant cells. It is located just outside the cell membrane and it provides the cells with structural support and protection. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the plant cells. The strongest component of the cell wall is a carbohydrate called cellulose , a polymer of glucose. The cell wall gives rigidity and strength to the plant cells which offers protection against mechanical stress. It also permits the plants to build and hold its shape. It limits the entry of large molecules that may be toxic to the cell.

It also creates a stable osmotic environment by helping to retain water, which helps prevent osmotic lysis. While the cell wall is rigid, it is still flexible and so it bends rather than holding a fixed shape due to its tensile strength. The rigidity of primary plant tissues is due to turgor pressure and not from rigid cell walls. This is evident in plants that wilt since the stems and leaves begin to droop and in seaweed that bends in water currents. This proves that the cell wall is indeed flexible. The rigidity of healthy plants is due to a combination of the cell wall construction and turgor pressure. The rigidity of the cell wall is also affected by the inflation of the cell contained. This inflation is a result of the passive uptake of water. Cell rigidity can be increased by the present of a second cell wall, which is a thicker additional layer of cellulose. This additional layer can be formed containing lignin in xylem cell walls, or containing suberin in cork cell walls. These compounds are rigid and waterproof, making the secondary cell wall very stiff. Secondary cell walls are present in both wood and bark cells of trees.

The primary cell wall of most plant cells is semi-permeable so that small molecules and proteins are allowed passage into and out of the cell. Key nutrients, such as water and carbon dioxide, are distributed throughout the plant from cell wall to cell wall via apoplastic flow. The major carbohydrates that make up the primary cell wall are cellulose, hemicellulose and pectin. The secondary cell wall contains a wide range of additional compounds that modify their mechanical properties and permeability. Plant cell walls also contain numerous enzymes, such as hydrolases, esterases, peroxidases, and transglycosylases, that cut, trim and cross-link wall polymers. The relative composition of carbohydrates, secondary compounds and protein varies between plants and between the cell type and age. There are up to three strata, or layers, that can be found in plant cell walls: The middle lamella, which is a layer rich in pectins. This is the outermost layer that forms the interface between adjacent plant cells and keeps them together. The primary cell wall which is generally a thin, flexible layer that is formed when the cell is growing.

The secondary cell wall which is a thick layer that is formed inside the primary cell wall after the cell is fully grown. It is only found in some cell types. A vacuole inside a plant cell. Vacuole[ edit ] The vacuole is essentially an enclosed compartment that is filled with water containing inorganic and organic molecules including various enzymes in solution. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these vesicles. This organelle does not have a basic shape or size since its structure is determined by the needs of the cell. The functions of the vacuole in the plant cell include isolating materials that may be harmful to the cell, containing waste products, maintaining internal hydrostatic pressure within the cell, maintaining an acidic internal pH, containing small molecules, exporting unwanted substances from the cell, and allowing plants to support structures such as leaves and flowers. Vacuoles also play an important role in maintaining a balance between biogenesis and degradation of many substances and cell structures in the organism. Vacuoles aid in the destruction of invading bacteria or of misfolded proteins that are building up within the cell.

They have the function of storing food and assist in the digestive and waste management process for the cell. Most mature plant cells have a single large central vacuole that takes up approximately 30% of the cell's volume. It is surrounded by a membrane called the tonoplast, which is the cytoplasmic membrane separating the vacuolar contents from the cell's cytoplasm. It is involved in regulating the movements of ions around the cell, and isolating substances that may be harmful to the cell. Other than storage, the main function of the central vacuole is to maintain turgor pressure against the cell wall. The proteins that are found in the tonoplast control the flow of water into and out of the vacuole through active trasnport, pumping potassium ions into and out of the vacuolar interior. Because of osmosis, water will flow into the vacuole placing pressure on the cell wall. If there is a significant amount of water loss, there is a decline in turgor pressure and the cell will plasmolyse. Turgor pressure exerted by the vacuole is required for cellular elongation as well as for supporting plants in the upright position.

Another function of the vacuole is to push all contents of the cell's cytoplasm against the cellular membrane which helps keep the chloroplasts closer to light. Plasmodesmata[ edit ] Plasmodesmata are microscopic channels that traverse the cell walls of plant cells enabling the transport and communication between the cells. Plasmodesmata enable direct, regulated intercellular transport of substances between the cells. There are two forms of plasmodesmata, primary ones that form during cell division and secondary ones that form between mature cells. They are formed when a portion of the endoplasmic reticulum is trapped across the middle lamella as a new cell wall is laid down between two newly divided plant cells and this eventually becomes the cytoplasmic connection between the two cells. It is here that the cell wall is thickened no further and depressions or thin areas known as pits are formed in the walls. Pits usually pair up between adjacent cells. Plasmodesmata are constructed of three main layers, the plasma membrane, the cytoplasmic sleeve, and the desmotubule.

The plasma membrane part of the plasmodesmata is an extension of the cell membrane and it is similar in structure to the cellular phospholipid bilayers. The cytoplasmic sleeve is a fluid-filled space that is enclosed by the plasma membrane and is an extension of the cytosol. The trafficking of molecules and ions through the plasmodesmata occurs through this passage. Smaller molecules, such as sugars and amino acids, and ions can pass through the plasmodesmata via diffusion without the need for additional chemical energy. Proteins can also pass through the cytoplasmic sleeve but it is not yet known just how they are able to pass through. Finally, the desmotubule is a tube of compressed endoplasmic reticulum that runs between adjacent cells. There are some molecules that are known to pass through this tube but it is not the main route for plasmodesmatal transport. The plasmodesmata have been shown to transport proteins, short interfering RNA, messenger RNA, and viral genomes from cell to cell. The size of the molecules that can pass through the plasmodesmata is determined by the size exclusion limit. This limit is highly variable and is subject to active modification.

There have been several models that have been proposed for the active transport through the plasmodesmata. One suggestion is that such transport is mediated by the interactions with proteins that are localized on the desmotubule, and/or by chaperones partially unfolding proteins which allows them to fit through the narrow passage. Plastid[ edit ] Plastids are the site of manufacture and storage of important chemical compounds that are used by the cell. They often contain pigments used in photosynthesis and the types of pigments present can change or determine the color of the cell. Plastids are responsible for photosynthesis, storage of products like starch, and the ability to differentiate between these and other forms. All plastids can be traced back to proplastids, which happen to be present in the meristematic regions of the plant. In plants, plastids may differentiate into several forms depending on what function they need to play in the cell. Undifferentiated plastids, the proplastids, can develop into the following types of plastids: •Chloroplasts: for photosynthesis •Chromoplasts: for pigment synthesis and storage •Leucoplasts: for monoterpene synthesis The inside of a chloroplast.

Chloroplasts are the organelles that conduct photosynthesis. They capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH. They are observed as flat discs usually 2 to 10 micrometers in diameter and 1 micrometer thick. The chloroplast is contained by an envelope that consists of an inner and outer phospholipid membrane. Between these layers is the intermembrane space. The material within the chloroplast is called the stroma and it contains many molecules of small, circular DNA (though it is often found in branched linear form, such as in corn). Within the stroma are stacks of thylakoids, which are the site of photosynthesis. The thylakoids are arranged in stacks called grana. A thylakoid has a flattened disk shape and has an empty space called the thylakoid space or lumen. The process of photosynthesis takes place on the thylakoid membrane. Embedded in the thylakoid membrane are antenna complexes that consist of the light-absorbing pigments, such as chlorophyll and carotenoids, as well as the proteins that bind the pigments.

These complexes increase the surface area for light capture and allows the capture of photons with a wider range of wavelengths. The energy of the incident photons is absorbed by the pigments and funneled to the reaction center of the complex through resonance energy transfer. From there, two chlorophyll molecules are ionized, which produces an excited electron which passes on to the photochemical reaction center. Chromoplasts are responsible for pigment synthesis and storage. They are found in the colored organs of plants such as fruit and floral petals, to which they give their distinctive colors. This is always associated with a massive increase in the accumulation of carotenoid pigments. Chromoplasts synthesize and store pigments such as orange carotene, yellow xanthophylls and various other red pigments. The most probably main evolutionary role of chromoplasts is to act as an attractant for pollinating animals or for seed dispersal via the eating of colored fruits. They allow for the accumulation of large quantities of water-insoluble compounds in otherwise watery parts of plants. In chloroplasts, some carotenoids are used as accessory pigments in the process of photosynthesis where they act to increase the efficiency of chlorophyll in harvesting light energy.

When leaves change color during autumn, it is because of the loss of green chlorophyll unmasking these carotenoids that are already present in the leaves. The term "chromoplast" is used to include any plastid that has pigment, mainly to emphasize the contrast with leucoplasts which are plastids that have no pigments. Leucoplasts lack pigments and so they are not green. They are located in roots and non-photosynthetic tissues of plants. They can become specialized for bulk storage of starch, lipid or protein and are then known as amyloplasts, elaioplasts, or proteinoplasts, respectively. In many cell types, though, leucoplasts do not have a major storage function and are present to provide a wide range of essential biosynthetic functions, including the synthesis of fatty acids, many amino acids, and tetrapyrrole compounds such as haem. Extensive networkds of stromules interconnecting leucoplasts have been observed in epidermal cells of roots, hypocotyls and petals. What are chloroplasts? | Socratic What are chloroplasts?

Start with a one sentence answer Then teach the underlying concepts Don't copy without citing sources Write a one sentence answer... Answer: I want someone to double check my answer Describe your changes (optional) 200 Cancel Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. Explanation: 1)Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis . Chloroplasts are the food producers of the cell 2) chloroplasts capture light energy from the sun to conserve free energy in the form of ATP 3)Chloroplasts are approximately 4 to 6 micrometers in diameter and shaped like a satellite dish with the concave face toward the light. 4. Chloroplasts are organelles found in plant cells and other - BIO - 1140 View Full Document Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. They capture light energy to conserve free energy in the form of ATP • Cell Wall For support 7.

Describe, with support, one theory on the origins of eukaryotic cells Endosymbiosis is the idea that certain organelles found in eukaryotic cells today, like mitochondria and chloroplasts were originally separate prokaryotic organisms which were absorbed into larger prokartotic cells and had a symbiotic relationship with them. Over time, they evolved along with the cells until they became inseparable parts of the same organism. Evidence for this is based on the following: 1. Mitochondria and chloroplasts are similar in size and morphology to bacterial prokaryotic cells 2. Mitochondria and chloroplasts divide by binary fission, just as bacteria do, and not by mitosis as eukaryotes do This preview has intentionally blurred sections. Sign up to view the full version. View Full Document 3. Chemically distinct membrane systems: The inner membrane is of a different chemical composition – like that of eubacteria – than the outer membrane of the organelle. Some enzymes and inner membrane systems resemble prokaryotic inner membrane systems. 4. Mitochondria and chloroplasts have their own DNA and their own ribosomes 5.

Mitochondria arise from preexisting mitochondria; chloroplasts arise from preexisting chloroplasts 6. Organelle ribosomes are more similar in size to prokaryotic ribosomes This is the end of the preview. Sign up to access the rest of the document. TERM Bio 1140 KMG Topic 1-chemistry of life University of Ottawa Bio 1140 KMG Topic 1- Chemistry of Life 1. Distinguish among monomers, polymers and m Bio 1140 KMG Topic 1-chemistry of life CELLS - Home CELLS Organelles Title. Chloroplasts are organelles found in plant cells and other eukaryoticorganisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADA to NADPH through a complex set of processes called photosynthesis. Title. Paragraph. Title. THE MITOCHONDRION IS A MEMBRANE ENCLOSED FOUND IS MOST EUKARYOTIC CELLS. THIS IS THE CELLULAR ENERGY. Title.

THE ENDOPLASMIC RETICULUM IS REPSONIBLE FOR PORDUCTION OF PROTEINS AND LIPIDS. Title. THE GOLGI IS THE FUNCTION OF MODIFY AND PACKAGE PROTEIN AND OTHER MATERIALS FROM THE ENDOPLASMIC RETICULUM FOR STORAGE IN THE CELL OR SECRETION OUTSIDE THE CELL. Title. THE CELL WALL IS MOST COMMONLY FOUND IN PLANT CELL. THE PRIMARY CELL WALL IS EXTREMELY ELASTIC, THE SECONDARY CELL WALL FORMS AROUND PRIMARY CELL WALL AFTER GROWTH IS COMPLETE. Title. CHROMOSOMES USALLY ARE IN A FORM OF CHROMATIN THEY CONTAIN GENETIC INFORMATION,COMPOSED OF DNA ,AND THICKEN FOR CELLULAR DIVISION. Title. THE NUCLEOLUS HAS A SPHERICAL SHAPE,IT IS VISIBLE WHEN CELL IS NOT DIVIDING AND CONTAINS RNA FOR PROTEIN MANUFACTURE. Title. EACH CELL CONTAINS THOUSANDS OF RIBOSOMES. THE RIBOSOMES MAKE PROTEIN WHICH ARE USED WITHIN THE CELL. Title.

MEMBRANE BOUND SACS FOR STORAGE,DIGESTION,AND REMOVAL WASTE AND CONTRACTILE VACUOLES FOR REMOVAL WATER IN UNICELLULAR ORGANISMS. Create a free website Molecular Expressions Cell Biology: Plant Cell Structure - Chloroplasts Chloroplasts One of the most widely recognized and important characteristics of plants is their ability to conduct photosynthesis, in effect, to make their own food by converting light energy into chemical energy. This process occurs in almost all plant species and is carried out in specialized organelles known as chloroplasts. All of the green structures in plants, including stems and unripened fruit, contain chloroplasts, but the majority of photosynthesis activity in most plants occurs in the leaves. On the average, the chloroplast density on the surface of a leaf is about one-half million per square millimeter. Chloroplasts are one of several different types of plastids, plant cell organelles that are involved in energy storage and the synthesis of metabolic materials. The colorless leucoplasts, for instance, are involved in the synthesis of starch, oils, and proteins.

Yellow-to-red colored chromoplasts manufacture carotenoids, and the green colored chloroplasts contain the pigments chlorophyll a and chlorophyll b, which are able to absorb the light energy needed for photosynthesis to occur. All plastids develop from tiny organelles found in the immature cells of plant meristems (undifferentiated plant tissue) termed proplastids, and those of a particular plant species all contain copies of the same circular genome. The disparities between the various types of plastids are based upon the needs of the differentiated cells they are contained in, which may be influenced by environmental conditions, such as whether light or darkness surrounds a leaf as it grows. The ellipsoid-shaped chloroplast is enclosed in a double membrane and the area between the two layers that make up the membrane is called the intermembrane space. The outer layer of the double membrane is much more permeable than the inner layer, which features a number of embedded membrane transport proteins. Enclosed by the chloroplast membrane is the stroma, a semi-fluid material that contains dissolved enzymes and comprises most of the chloroplast's volume.

Since, like mitochondria, chloroplasts possess their own genomes (DNA), the stroma contains chloroplast DNA and special ribosomes and RNAs as well. In higher plants, lamellae, internal membranes with stacks (each termed a granum) of closed hollow disks called thylakoids, are also usually dispersed throughout the stroma. The numerous thylakoids in each stack are thought to be connected via their lumens (internal spaces). Light travels as packets of energy called photons and is absorbed in this form by light-absorbing chlorophyll molecules embedded in the thylakoid disks. When these chlorophyll molecules absorb the photons, they emit electrons, which they obtain from water (a process that results in the release of oxygen as a byproduct). The movement of the electrons causes hydrogen ions to be propelled across the membrane surrounding the thylakoid stack, which consequently initiates the formation of an electrochemical gradient that drives the stroma's production of adenosine triphosphate (ATP). ATP is the chemical energy "currency" of the cell that powers the cell's metabolic activities.

In the stroma, the light-independent reactions of photosynthesis, which involve carbon fixation, occur, and low-energy carbon dioxide is transformed into a high-energy compound like glucose. Plant cells are remarkable in that they have two organelles specialized for energy production: chloroplasts, which create energy via photosynthesis, and mitochondria, which generate energy through respiration, a particularly important process when light is unavailable. Like the mitochondrion, the chloroplast is different from most other organelles because it has its own DNA and reproduces independently of the cell in which it is found; an apparent case of endosymbiosis. Scientists hypothesize that millions of years ago small, free-living prokaryotes were engulfed, but not consumed, by larger prokaryotes, perhaps because they were able to resist the digestive enzymes of the engulfing organism. According to DNA evidence, the eukaryotic organisms that later became plants likely added the photosynthetic pathway in this way, by acquiring a photosynthetic bacterium as an endosymbiont. As suggested by this hypothesis, the two organisms developed a symbiotic relationship over time, the larger organism providing the smaller with ample nutrients and the smaller organism providing ATP molecules to the larger one.

Eventually, the larger organism developed into the eukaryotic cell, the smaller organism into the chloroplast. Nonetheless, there are a number of prokaryotic traits that chloroplasts continue to exhibit. Their DNA is circular, as it is in the prokaryotes, and their ribosomes and reproductive methods (binary fission) are more like those of the prokaryotes. Topic 6: Photosynthesis - Biology 212 with Chang at Oregon State University - StudyBlue Size: 37 Views: 25 Chloroplast Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis. Stroma The matrix surrounding the grana in the inner membrane of chloroplasts. The area between membranes (thylakoids, grana) inside the chloroplast. a mass of fungal tissue that has spore-bearing structures embedded in it or on it. The dense colorless framework of a chloroplast. The supporting tissue of an organ (as opposed to parenchyma).

Advertisement ) A stack-like structure in plant chloroplasts that contain chlorophyll; the site of photosynthesis. Stroma Lamellae In higher plants, lamellae, internal membranes with stacks (each termed a granum) of closed hollow disks called thylakoids, are also usually dispersed throughout the stroma. Thylakoid A thylakoid is a membrane-bound compartment inside chloroplasts and cyanobacteria. They are the site of the light-dependent reactions of photosynthesis. The word "thylakoid" is derived from the Greek thylakos, meaning "sac". Electromagnetic Spectrum The entire frequency range of electromagnetic waves. The whole range of radiation that travels through a vacuum with a speed of about 3 × 10^8 meters per second. Reaction Center A photosynthetic reaction centre is a complex of three types of protein that is the site where molecular excitations originating from sunlight give rise to a series of electron-transfer reactions Light Reaction The first stage of photosynthesis during which energy from light is used for the production of ATP. Phosphorylation The production of ATP using the energy of sunlight is called photophosphorylation.

Only two sources of energy are available to living organisms: sunlight and oxidation-reduction (redox) reactions. All organisms produce ATP, which is the universal energy currency of life. Calvin Cycle The second of the two major steps of photosynthesis (the other being the light reactions). The cycle fixes CO2 and produces carbohydrates. The Calvin cycle or Calvin-Benson cycle or Dark Reaction is a series of biochemical reactions that take place in the stroma of chloroplasts in photosynthetic organisms. Cyclic Electron Flow The light-requiring part of photosynthesis in higher plants, in which an electron donor is required, and oxygen is produced as a waste product. It consists of two photoreactions, resulting in the synthesis of ATP and NADPH2. The hydrogen needed for the reduction of NADP (nicotinamide adenine dinucleotide phosphate) is made available from the breakdown of water. Photon An elementary particle, the quantum of the electromagnetic interaction and the basic "unit" of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force.

Rubisco Most commonly known by the shorter name RuBisCO,[1] is an enzyme involved in the Calvin cycle, that catalyzes the first major step of carbon fixation, a process by which the atoms of atmospheric carbon dioxide are made available to organisms in the form of energy-rich molecules such as glucose. RuBisCO catalyzes either the carboxylation or the oxygenation of ribulose-1,5-bisphosphate (also known as RuBP) with carbon dioxide or oxygen. Absorption Spectrum The relative tendency of a material to absorb a specific color or energy of light, typically plotted as intensity, transmission, or optical density versus wavelength. null The molecule that CO2 reacts with in photosynthetic carbon fixation. The enzyme ribulose biphosphate carboxylase oxygenase (RuBisCO) catalyzes RuBP with CO2 in order to synthesize a highly unstable 6-C intermediate aka 3-keto-2-carboxyarabitinol 1,5-biphosphate, which decays virtually instantaneously into 2 molecules of glycerate 3-phosphate (G3P) (see Calvin Cycle). RuBP is both used and created during the Calvin Cycle.

It is a product of the phosphorylation of ribulose-5-phosphate by ATP. Advertisement ATP Synthase A general term for an enzyme that can synthesize ATP from ADP and inorganic phosphate by using a form of energy. A cluster of several membrane proteins foudn int he mitochondrial crista that function into chemiosmosis with adjacent e- transport chains, using the energy of a hydrogen ion concentration gradient to make ATP. Enzyme that catalyses the phosphorylation of ADP to ATP during oxidation phosphorylation in mitochondria or photophosphorylation in photosynthetic organisms. Glyceraldehyde-3-phosphate (G3P) Is an intermediate in the Calvin cycle (see also photosynthesis) and glycolysis. A chemical compound that occurs as an intermediate in several central metabolic pathways of all organisms. It is a phosphate ester of the 3-carbon sugar glyceraldehyde and has chemical formula C3H7O6P. Carotenoid Any of a class of highly unsaturated yellow to red pigments occurring in plants and animals.

Carotenoids are organic pigments that are naturally occurring in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, some types of fungus and some bacteria. Photorespiration (or "photo-respiration") is the process by which RuBP, (a sugar) has oxygen added to it by the main enzyme involved in photosynthesis, rubisco, instead of carbon dioxide as happens during photosynthesis. Metabolic pathway that uses oxygen and produces CO2. Photosystems Functional and structural units of protein complexes involved in photosynthesis that together carry out the primary photochemistry of photosynthesis; the absorption of light and the transfer of energy and e-. They are found in the thylakoid membranes of plants, algae and cyanobacteria (in plants and algae located in chloroplasts), or in the cytoplasmic membrane of photosynthetic bacteria. At the heart of a photosystem lies the Reaction center, an enzyme that uses light to reduce molecules.

C4 Plant C4 Carbon fixation is one of 3 biochemical mechanisms, along with C3 and CAM photosynthesis, function in in land plants to "fix" CO2 (binding the gaseous molecules to dissolved compounds inside the plant) for sugar production through photosynthesis. Plants whereby the 1st organic product of carbon-fixation is a 4-c compound, formed prior to the Calvin cycle. This adaptation is advantageous in hot regions with intense sunlight as it minimizes photorespiration and maximizes sugar production. CAM Plant Crassulacean acid metabolism, also known as CAM photosynthesis, is an elaborate carbon fixation pathway in some plants. These plants fix carbon dioxide during the night, storing it as the four carbon acid malate. Standing for crassulacean acid metabolism, this is a type of plant that employs an alternative photosynthesis pathway where CO2 enters the open stomata of the leaf during the night, allowing the stomata to close during the day to reduce water loss. Pigment What is the function of the chloroplasts? - OpenStudy What is the function of the chloroplasts?

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Question: Capturing light energy to conserve free energy in the form of ATP, which organelles found in plant cells conduct photosynthesis?
Answer: CHLOROPLASTS